EPISODIC TECTONIC EVOLUTION,BASIN TYPES AND HYDROCARBON ACCUMULATION IN CHINESE MARGINAL BASINS

Chinese marginal basins,located in the most active region where the Eurasia plate、India-Australia plate and the Pacific plate converge,have suffered multiphase tectonic activities since Paleocene,especially strong neotectonic movements since Miocene. Under such a regional geological background,Chinese marginal basins are characterized by episodic tectonic evolution,and a "trench-arc-basin" system is gradually formed that resulted in the formation of a series of Cenozoic basins with fault-depression structure in shallow and deep waters,in which filled with medium to deep water lacustrine facies and source rocks in the early faulting stage of Paleogene, coal measures and source rocks in the late faulting stage and marine deposits and source rocks in the stage of Neogene. The evolutionary history laid a solid material foundation for hydrocarbon generation. The subsidence-depositional centers of marginal basins gradually migrated with time from continent to ocean,are favorable for the formation of multiple reservoir-seal assemblages. The temporal and spatial intercoupling with neotectonic movement and hydrocarbon supply system become the major factor which affects the hydrocarbon accumulation in marginal basins.